How to Make a Triangle in Computer Generated Art
▲ Triangle is a tool for generating triangulated epitome using delaunay triangulation. It takes a source image and converts it to an abstract image composed of tiles of triangles.
The procedure
- Commencement the paradigm is blured out to smoth out the sharp pixel edges. The more than blured an image is the more diffused the generated output will be.
- Second the resulted image is converted to grayscale fashion.
- Then a sobel filter operator is applied on the grayscaled image to obtain the paradigm edges. An optional threshold value is applied to filter out the representative pixels of the resulted image.
- A convolution filter operator is practical over the image information in gild to adjust its last aspect prior running the delaunay triangulation process.
- Lastly the delaunay algorithm is applied on the pixels obtained from the previous stride.
Features
- Tin process recursively whole directories and subdirectories meantime.
- Supports various image types.
- There is no need to specify the file type, the CLI tool tin recognize automatically the input and output file type.
- Tin can take epitome URL equally parameter for the
-inflag. - Possibility to salve the generated image as an SVG file.
- The generated SVG file can exist accessed from the Spider web browser direct.
- Clean and intuitive API. The API non just that accepts image files but can besides work with image data. This means that the
Drawmethod can be invoked fifty-fifty on data streams. Check this demo for reference. - Support for pipage names (possibility to pipage in and pipe out the source and destination image).
TODO
- Standalone and native GUI application
Caput over to this subtopic to get a ameliorate understanding of the supported features.
Installation and usage
$ go get -u -f github.com/esimov/triangle/cmd/triangle $ go install You tin besides download the binary file from the releases binder.
MacOS (Brew) install
The library can be installed via Homebrew as well.
API usage
proc := &triangle.Processor{ MaxPoints: 2500, BlurRadius: 2, PointRate: 0.75, BlurFactor: 1, EdgeFactor: vi, } img := &triangle.Image{ Processor: * proc, } input, err := os.Open("input.jpg") if err != nil { log.Fatalf("error opening the source file: %v", err) } // decode image src, err := img.DecodeImage(input) if err != nil { log.Fatalf("mistake decoding the paradigm: %5", err) } res, _, _, err := img.Draw(src, * proc, func() {}) if err != zilch { log.Fatalf("error generating the triangles: %v", err) } output, err := os.Create("output.png") if err != nil { log.Fatalf("fault opening the destination file: %v", err) } // encode image png.Encode(output, res) Supported commands
The following flags are supported:
| Flag | Default | Description |
|---|---|---|
in | due north/a | Source image |
out | n/a | Destination paradigm |
bl | 2 | Blur radius |
nf | 0 | Dissonance cistron |
bf | 1 | Blur factor |
ef | 6 | Edge factor |
pr | 0.075 | Signal rate |
pth | x | Points threshold |
pts | 2500 | Maximum number of points |
and so | x | Sobel filter threshold |
sl | imitation | Use solid stroke color (aye/no) |
wf | 0 | Wireframe way (0: without stroke, ane: with stroke, ii: stroke only) |
st | i | Stroke width |
gr | false | Output in grayscale mode |
web | imitation | Open the SVG file in the web browser |
bg | ' ' | Background color (specified as hex value) |
cw | system spec. | Number of files to process concurrently |
Cardinal features
Process multiple images from a directory concurrently
The CLI tool also let y'all process multiple images from a directory concurrently. Yous only need to provide the source and the destination folder by using the -in and -out flags.
$ triangle -in <input_folder> -out <output-folder> Y'all tin provide as well an paradigm file URL for the -in flag.
$ triangle -in <image_url> -out <output-folder> Pipe names
The CLI tool accepts also pipage names, which ways y'all can use stdin and stdout without the demand of providing a value for the -in and -out flag directly since these defaults to -. For this reason it's possible to use curl for instance for downloading an image from the internet and invoke the triangulation process over it directly without the need of getting the image first and calling ▲ Triangle afterwards.
Here are some examples using pipage names:
$ ringlet -south <image_url> | triangle > out.jpg $ cat input/source.jpg | triangle > out.jpg $ triangle -in input/source.jpg > out.jpg $ cat input/source.jpg | triangle -out out.jpg $ triangle -out out.jpg < input/source.jpg
Background color
You tin specify a background color in instance of transparent background images (.png) by using the -bg flag. This flag accepts a hexadecimal string value. For example setting the flag to -bg=#ffffff00 will fix the alpha channel of the resulted paradigm transparent.
Output equally image or SVG
By default the output is saved to an image file, but you can export the resulted vertices even to an SVG file. The CLI tool can recognize the output blazon directly from the file extension. This is a handy addition for those who wish to generate large images without guality loss.
$ triangle -in samples/input.jpg -out output.svg Using with -web flag you tin can access the generated svg file directly on the web browser.
$ triangle -in samples/input.jpg -out output.svg -web=true Supported output types
The post-obit output file types are supported: .jpg, .jpeg, .png, .bmp, .svg.
Tweaks
Setting a lower points threshold, the resulted epitome volition be more than like a cubic painting. You tin even add together a noise factor, generating a more artistic, grainy image.
Here are some examples you can experiment with:
$ triangle -in samples/input.jpg -out output.png -wf=0 -pts=3500 -st=2 -bl=2 $ triangle -in samples/input.jpg -out output.png -wf=2 -pts=5500 -st=one -bl=x Examples
License
Copyright © 2018 Endre Simo
This project is nether the MIT License. See the LICENSE file for the full license text.
Source: https://github.com/esimov/triangle
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